Circuit breaker



July 21, H s, GANO ET AL 2,048,114

CIRCUIT BREAKER Filed March 23, 1932 3 Sheets-Sheet l aim/5555. J? INVEgTORS 4 415 4170mm v fl /kz'fljayvzazz Ga; M' \7, I i

ATTORNEY J y 1936- H. s. GANO ET AL 2,048,114

C IRCUIT BREAKER Filed March 25, 1932 3 Sheets-Sheet 2 WITNESSES: INVENTORS 156/222564220414 6 flY/ZWfiflor z7fd/7. O 1 MT BY ATTORNEY y 1936- H. s. GANO ET AL 2,048,114

CIRCUIT BREAKER Filed March 23, 1932 3 Sheets-Sheet 3 gWglESSES: "1%ENTORS M 4/072 @170 d jg/Z flfiay maz.

Patented July 21, 1936 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Pennsylvania Application March 23, 1932, Serial No. 600,658

57 Claims.

Our invention relates to circuit breakers and particularly to circuit breakers of the type in which the breaker operating means is manually actuable to open or close the circuit, and is automatically actuable to open the circuit and to prevent the closing of the circuit upon short circuit or overload conditions.

One object of our invention is to provide a circuit breaker having a trip mechanism capable of opening the breaker immediately upon the occurrence of a short circuit, andcapable of opening the breaker after a predetermined time interval upon the occurrence of an overload condition.

Another object of our invention is to provide a trip mechanism for circuit breakers having a core member of magnetic material, an armature, and a loop of thermally responsive material for exciting the core member.

A further object of our invention is to provide a trip mechanism for circuit breakers having a plurality of coil members, each associated with a pole piece, and an armature common to two or more coil members.

A further object of our invention is to provide a trip mechanism for a multi-pole circuit breaker having a thermally responsive and a magnetically responsive element associated with each pole thereof, and a means engageable and operable by any one of said thermally responsive or said magnetically responsive elements to trip all of the poles of said breaker.

A still further object of our invention is to provide a trip mechanism for a multi-pole circuit breaker which shall be capable of opening all of the poles of the breaker immediately upon the occurrence oi. a short circuit and after a. predetermined time interval upon the occurrenceof an overload condition, which shall be capable of tripping the breaker irrespective of the position of the operating handle, and which shall be resettable to the operative position by means associated with the operating handle.

The principal field for immediate application of our invention is in connection with multi-poie circuit breakers for controlling lighting and distribution feeder circuits, and we shall hereinafter describe an embodiment of our invention as applied to such circuit breakers, without in any way intending to restrict the scope of our invention except as indicated in the appended claims.

In this embodiment of our invention, we provide a plurality of switch members and a plurality of stationary contact members for opening a plurality .of poles. In addition, we provide a Fig. 1, certain of the parts are shown in elevation 25 the cover Il.

manually operable mechanism for opening and closing the breaker contacts with a snap action, an insulating base upon which the structure is assembled, an arc extinguishing device for each pole, a means for biasing each of the switch mem- 5 bers to the open position, a releasable restraining means for holding all of the switch members closed, and a unitary trip device for releasing the restraining means in response to a predetermined electrical condition in any one pole, and thereby 10 opening all of the poles of the breaker; the releasing means being operable to open the breaker regardless of the position of the operating handle.

The features of our invention which we believe to be new are particularly pointed out in the appended claims. For a. full understanding of the principles of the invention reference may be had to the accompanying drawings, in which:

Figure 1 is a plan view'of a three-pole circuit breaker embodying the principal elements of our invention, the cover has been cut away to show part of the breaker mechanism and part of the trip structure;

Fig. 2 is a sectional view on the line 11-11 of to more clearly illustrate the structural features involved; a

Fig. 3 is a fragmentary perspective view showing the trip device and part of the breaker operating mechanism of our invention. Referring to the drawings, the base I is of molded insulating material, and, has mounted thereon the terminal contacts 3 and 4, the unitary trip device 5, the circuit breaker operating mechanism l which has associated therewith the assemblage of the switch members 9, the are ex tinguishers l I, and the stationary contact assemblages I3. The switch members 9 and the stationary contact assemblages I3 combine to form the plurality of poles. Each of the poles is insulated from the adjacent pole by means or one of the insulating baffles l5 which are molded in the base I. The insulating battles I5 align with similarly shaped bafiies I9 in the cover I! which is likewise of molded insulating material; The

operating handle 2|, which is rigidly fixed to the switch operating mechanism 1, is also of molded insulating material, and it has a portion 23 which projects through a suitable opening 24 in The unitary trip device 5 has a base 25 of insulating material which engages a suitable recess 21 in the insulating base I. The cover 29 of the unitary trip device 5 is of molded insulating material and is so proportioned that it aligns with and engages the cover I1 of the circuit breaker proper.

The electrical circuit for each of the poles is substantially the same. Beginning with the terminal contact 3 the current passes successively through the stationary contact assemblage I3, the switch member 9 and its associated conducting shunts I0, the unitary trip device 5-the shunts I0 connecting with the conducting strips I06 of the trip device-and thence to the other terminal contact 4.

Each of the stationary contact assemblages I3 comprises a conducting strip 34 which is fastened to the base I by means of the screw 39 and its associated nut H, and a stationary contact 35 which is rigidly affixed to the conducting strip 34. Suitable holes 30 are provided in the base I for the reception of the screws 3! which, with the nuts 33, connect the conducting strips 34 and the terminal contacts 3.

Each of the switch members 9 has an iron frame 43 upon which the remainder of the structure is assembled. Fastened to the lower side of the frame 43, by means of two rivets 46, is a fiat spring member 44 having associated therewith two contacts 31 for engaging the stationary contacts 35. Two of the shunts I0 are welded to the spring member 44 adjacent to the contacts 31, and serve to provide a low resistance conducting path from those contacts to the trip device 5. Two pins 48 are rigidly affixed to the free end of the spring member 44 and extend upwardly through guide holes 50 in the iron frame 43. Springs 52, positioned between the spring member 44 and the frame 43, are provided for establishing proper contact pressure between the contacts 35 and 31. The cotter pin 54 prevents the pins 48 from passing downwardly through the holes 50 when the breaker is in the open position.

All three of the frames 43 of the switch members 9 have a square opening 45 therein. An insulating bar 41, which extends across all of the poles of the breaker engages three openings 45, and thereby provides a means whereby all of the circuit breaker contacts may be opened and closed simultaneously by the single operating mechanism 1. As will be more fully pointed out later, the three switch members 9 and their connecting bar 41 are pivoted about a pin 11 which forms a part of the operating mechanism 1.

We prefer to use are resisting material for the contacts 35 and 31, the former being composed of finely divided silver and graphite pressed into a conglomerate mass, and the latter being composed of a silver-molybdenum alloy.

The are extinguishers II are of the spacedplate type in which a plurality of slotted magnetic plates, each insulated from the other, and having slots therein, are provided. These extinguishers are disposed adjacent to the arc paththe slots being of substantially the same outline as the moving contacts-and upon the establishment of an arc, due to the altering of the magnetic circuit adjacent to the arc path, force the arc to move into the spaces between the plates where it is quickly cooled and extinguished.

In the .structure which we prefer to use, the magnetic plates 55 having slots 56 therein are assembled between two end plates 51 of insulating material, projecting lugs (not shown), being provided in the magnetic plates for engaging the end plates 51. The insulating end plates 51 have a slot I9 therein. In the assembled breaker structure an insulating member BI which forms a part of the cover I! engages the slot 59 and serves to more completely separate the arc chamber from the remainder of the structure. This gives an increased margin of safety when interrupting heavy arc currents because it helps to prevent fiashovers between the,poles.

The operating mechanism 1 comprises, in general, a U-shaped base 53, a pair of toggle links 55 and 61 for engaging the switch members 9, a trigger 69 for releasably restraining the toggle links 65 and 61 in operative position, an operating lever 1I, springs 13 for connecting the operating lever H to the knee of the toggle links, and the operating handle 2I. The U-shaped base 63 is fastened to the insulated base I of the circuit breaker proper by means of two screws 15. A pin 11 extends through aligned openings in the U-shaped base and provides a pivot point for the moving contacts 9, all of which are mechanically tied together by the insulating bar 41. Other holes are provided for the reception of the pivot pins 19-one on either side of the Uwhich provide pivot points for the bifurcated operating lever H. The lower end (with reference to the base I) of the toggle link 65 is pivoted to the central moving contact 9 by the pin 18. The upper end is pivoted to the second toggle link 61 by means of the pin BI. On either end of the pin BI there is pivoted a member 83 which is engaged by the four operating springs 13, two on either side. The trigger 69, which is pivoted about the pin 85, provides a releasable restraining means for holding the toggle links 65 and 51 in the operative position. The movement of the trigger 69, in a clockwise direction, is limited by the projection 81 which extends inwardly from one side of the U-shaped base 53. The free end 88 of the toggle link 51 is notched; this notched end 68 engages a suitable recess 89 in the trigger 69 and pivots therein. The movement of the bifurcated operating member H is limited by the projections SI and 93 of the U-shaped base, the lower extremities of the operating member 1| being bent outwardly to clear the projections and to engage the pivot pin 19. The projecting end 95 of the trigger 69 is engaged by the trip means associated with the trip device 5.

As previously pointed out, the trip device 5 is a unitary structure, entirely assembled upon its own insulating base 25, and completely removable from the breaker; the screws 91 and 99 which engage suitable threaded members 98 and I00 imbedded in the base I, being provided for this purpose. The trip device 5 includes a thermallyresponsive element IOI and a magnetically responsive element for each pole of the breaker. Each thermally responsive element IN is composed of bimetallic material and comprises a pair of leg portions I00a joined to each other at one end by a connecting portion I02 so as to form a substantially U shaped conducting loop, and a portion I04 which extends outwardly from the loop. Connecting strips I05 and I 05 are riveted to the opposite erids of the U, and connect respectively, to the terminal contact 4 and the shunts I0- suitable holes being provided to permit the passage of the screws 91 and 99. The screws I08 and I I0 which pass through the openings I I2 and H4 in the trip base 25, engage the thread holes IIS and H8 in the members I05 and I06 and serve to fasten those members to the base 25. A pole piece I01, substantially E shaped and of magnetic material, is disposed adjacent to the bimetallic element IIlI, the central part of the E extending between the loop formed by the two legs Illtla which make up the U. Thus, the current flowing in the conducting loop formed by the bimetal energizes the pole piece I01. A single armature I09 extending across all three poles is provided; this comprises a flat strip of iron having projecting lugs III at either end for engaging the pivot pins I I3, and a projection I I5 which extends outwardly from the armature proper. The function of this projection II5 will be described in some detail in a subsequent paragraph. An insulating member H1 is disposed between the E shaped pole pieces I91 and the armature I09, and provides an insulating means between the armature I09 and the pole peices I01; in addition it prevents sticking of the armature due to residual flux.

As previously pointed out, the trigger 69 is normaily biased in a clockwise direction (Fig. 2) by the operating springs 13, and must be restrained from such movement if the breaker is to be held closed. A latch member H9 is provided for this purpose. This member H9 is pivoted about the pin I2I which is mounted on a base member I22;' it is biased in a counter-clockwise direction (Fig; 2) about the pin I2I by the coil spring I23, has an opening I25 for engaging the end 95 of the trigger 89. and is restrained'from movement in the counter-clockudse direction by the trip bar I21 and its associated restraining means. Two screws I fasten the base member I22 to the insulating base 25 of the trip device. A projection I42 is provided on the latch I I9 for engaging the latch restraining means.

The common trip bar I21, which is actuable by any one of the thermally responsive elements IIlI or by any one of the magnetically responsive elements, extends across all three poles of the breaker. The lugs I39 are provided on the ends of the trip bar I21 for engaging the pivot pins I3I. The three projecting members I33 in combination with the insulating spacers I32 provide means for engaging the projections I94 of the thermally responsive elements I0 I. The insulating spacers I32 are adjustable by means of a threaded stud I36 which engages a threaded opening I38 in the projecting members I33. A spring I40 (Fig. 3) attached at one end to the base I22 of the latch member H9, and attached at the other end to the trip bar I21, provides a biasing means for maintaining the trip bar in an operative position and for making the trip device resettable. The latch restraining means comprises a plate I28, of iron, having a projection I29 for engaging the projection I42 of latch member H9. The plate I28 is rigidly aifixed to the trip bar I21 and is insulated therefrom by the rivets I34 and the mica insulatingmembers I35-suitab1e holes being provided in the trip bar for the rivets. The centrally disposed projecting member I33 of the trip bar I21 has an additional insulating member I31 aihxed thereto. This member I31 provides means whereby the projection II5 on the center of the armature I09 engages the trip bar I21.

Three vent openings I4I of substantially the same width as the plates of the arc extinguishing structures II are provided in the insulating cqver I1one for each pole of the breaker, and each separated from the adjacent one by the bafiles I9. These openings I4I are covered by a screen l43 to provide ventilation and at the same time to prerent flashovers between the poles. They connect with an open passage I44 which assists in the removal of the very large volumes of arc gases formed during the interruption of heavy currents.

Two screws I45, which extend through the openings I46 in the cover I1, engage the threaded openings I41 in the base I, and serve to fasten the cover I1 securely thereto. The trip cover 29 is similarly fastened to its base 25 by the screws I48, which pass through the openings I49 in the cover 29 and engage suitable means not shown) in the base 25. Two metallic restraining strips I59 fastened to the trip cover 29 by screws I5I engage recesses I52 in the breaker cover I1 and assist in retaining that cover in position. The openings I53 and I54, which extend entirely through the breaker, are provided for the reception of suitable mounting means.

Referring particularly to Figure 2, wherein the circuit breaker of our invention is in the closed position, it will be noted that the center of the toggle links and 61 has moved to the locked position. Thus the contacts 35 and 31 are held against each other with a substantially uniform contact pressure maintained by the springs 52.

To open the contacts manually the operatinghandle 23 is moved downwardly whereupon the springs 13 exert a force having a component tending to move the center pivot pin it of the toggle mechanism downwardly, or out of toggle. At a certain point this com :onent of force exerted by the springs 13 is sufficient to cause the toggle to break and move the switch members 9 counterclockwise about the pin 11, thus separating the contacts 35 and 31. The motion of the central switch member 9 is transmitted'to the switch members for the outer poles by the insulating bar 41, as has been previously pointed out. The closing process is substantially the reverse of the opening process, the central part 8| of the toggle links being moved, in this case, upwardly. The breaker is thus opened and closed with a snap action.

When the breaker is in the closed position and an overload comes upon the circuit controlled by any one of the poles, the bimetal element IDI in that pole is heated and bends downwardly (Fig. 2). Should the overload continue for a suffieient length of time, depending upon the calibration of the particular bimetal involved, the projection I94 will engage the insulating member I32, and

through it, move the trip bar I21 to a position which will disengage the projection I29 from the projection I42 of the trip latch II9. The trip latch II9 will then rotate in a counter-clockwise direction and will release the end 95 of the trigger 69, the trigger 69 will rotate clockwise about the pin 85, due to the biasing action of the springs 13, until it engages the projection 81. However, by this time the toggle link has moved to a position where the center pin BI is below the center line of the toggle. Thus. the toggle breaks toward the base of the trip device with a snap action as it did during the opening of the breaker by the operating handle.

The projection 22 on the operating handle .23 is provided for restoring the entire mechanism to an operative position. Following the tripping of the breaker by the trip device 5 the handle 23 may be moved downwardly, and the resulting engagement of the projection 22 and the trigger 69 will rotate the trigger counter-clockwise Fig. 2) until the projecting arm 95 engages the opening I25 in the trip latch II9. A further movement of the arm 23 causes the trip latch H9 to be rotated clockwise. and, simultaneously, causes (ill the movement of the projection M2 to the position where it again engages the projection I29 on the trip bar I21. The interrupter is now in the open position and may be closed by a move- .ment of the operating handle.

In the event of a short-circuit condition in any one of the circuits controlled by the various poles of the breaker, a sufficient magnetic attraction is set up by the looped bimetal lOl and its associated pole piece M7 to cause the common armature l09 to be attracted thereto. The armature,

in so moving, rotates about the pivot pins H3,

and the projection H5 engages and moves the common trip bar I27, thereby releasing the latch i i9. Thus, the circuit breaker may be tripped immediately uponthe occurrence of a short circult in any one of the controlled circuits, or after a predetermined time interval, due to an overload in any one of the controlled circuits.

Should an attempt be made to close the breaker when a short circuit exists in any one of the controlled circuits, the trip device would immediately release the trigger 69, thus breaking the toggle and opening the breaker, regardless of the position of the opera-ting handle 23.

It will be seen that we have disclosed a circuit breaker having a simplified trip mechanism capable of opening the breaker immediately upon the occurrence of a short circuit in any one of the controlled circuits, or after a predetermined time interval upon the occurrence of an overload in any one of the controlled circuits. It will also be seen that we have considerably improved upon existing structures of this type by utilizing the thermally responsive element as the energizing means for the magnetically responsive element, and that we have provided a structure wherein a single armature is attracted by a plurality of coil members, and wherein a common trip bar is engageable by any one of a plurality of thermally responsive elements and a plurality of magnetically responsive trip elements. Moreover, we have provided means for a structure having the abovementioncd features whereby the entire mecha nism may be returned to the operative position following each opening of the breaker by the trip device. 1

While in accordance with the patent statutes we have disclosed one embodiment of our invention. the principles herein involved are applicable to other structures, and we desire, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction, and that our invention be limited only by what is explicitly stated in the claims and by the prior art.

We claim as our invention:

1. A trip device for a circuit interrupter, including means of magnetic material, and magnetizing means for said means of magnetic matcrlel comprising a coil member of bimetallic thermaily responsive material, said coil member having a portion that is movable upon the occurrence of predetermined conditions to actuate said trip device.

2. A trip device for a circuit interrupter, including means of magnetic material, and energizing means for said means of magnetic material comprising a member of bimetallic thermally responsive material looped about said means of magnetic material, said looped member having a portion that is movable in a direction at right angles to the plane of said loop, upon the occurrence of predetermined conditions, to actuate said trip device.

3. A trip device for a circuit interrupter, including a pole piece of magnetic material and energizing means for said pole piece comprising a member of bimetallic thermally responsive material looped about said pole piece; the ends of said looped member of thermally responsive material being electrically connected in the circuit of said circuit interrupter, said looped member having a portion that is laterally movable upon the occurrence of predetermined conditions to actuate said device.

4. A trip device for a'circuit interrupter, including a substantially E shaped pole piece 0! magnetic material, and energizing means for said pole piece comprising a looped member of bimetallic thermally responsive material, said member of bimetallic material having a portion that is movable upon the occurrence of predetermined conditions to actuate said device.

5. A trip device for a circuit interrupter, including a current conducting member having a pair of leg portions, at least one of which is of bimetallic thermally responsive material, and means for electrically connecting said leg portions, and a magnetic member associated with said conducting member and having a portion extending between said leg portions, said portion of bimetallic material being laterally movable upon the occurrence of predetermined conditions to actuate said trip device.

6. A trip device for a circuit interrupter, including a substantially U shaped, current-carrying member of bimetallic material, a member of magnetic material having a portion extending between the sides of said U shaped bimetallic member, and a second member of magnetic material extending adjacent said U shaped bimetallic member, said U shaped member serving to energize said members of magnetic material to cause the actuation of said trip device upon the occurrence of predetermined conditions, said U shaped member including a portion, projecting outwardly from the closed end of said U, that is movable laterally upon the occurrence of predetermined conditions to actuate said trip device.

7. A trip device for a circuit interrupter, including a pole piece of magnetic material substantially in the form of an E, and a current conducting loop about the central portion of said pole piece, said current conducting loop having a portion of thermally responsive material that is movable upon the occurrence of predetermined conditions to cause the actuation of said trip device.

8. In a circuit interrupter, a plurality of switch members for opening a plurality-of poles, each of said switch members including a fixed contact and a moving contact, latching means releasable to cause a plurality of said moving contacts to move from the closed circuit to the open circuit position, and releasing means for said latching means, a plurality of thermally responsive elements, each electrically connected into the circuit controlled by one of said poles, and a magnetically responsive means having a portion associated with each of two or more poles of said interrupter, and a means for engaging said latch releasing means engageable and operable by any one of said thermally responsive elements or said magnetically responsive means associated with any one of said poles.

9. In a circuit interrupter, a plurality of switch members for opening a plurality of poles, latching means releasable to cause a plurality of said switch members to move from the closed circuit to the open circuit position, and releasing means for said latching means, including a coil member of bimetallic material associated with each of two or more poles of said circuit interrupter, and an armature common to two or more of said coil members, said coil members and said armature being individually movable to actuate said latch releasing means in response to predetermined electrical conditions.

10. In a circuit interrupter, a plurality of switch members for opening a plurality of poles, latching means releasable to cause a plurality of said switch members to move from the closed circuit to the open circuit position, and releasing means for said latching means, including a plurality oi! thermally responsive elements, a plurality oi magnetizing members, an armature common to two or more of said magnetizing members, and a means for engaging and operating said releasing means actuated by any one of said thermally responsive elements or by said common armature.

11. In a. circuit breaker, a plurality of contact members, a plurality of switch members for opening a plurality of poles, a latching means releasable to cause a plurality of said switch members to move from the closed circuit to the open circuit position, a plurality of separate independently operable trip devices, each having a pole piece of magnetic material, a conducting means for energizing said pole piece, and means of thermally responsive material associated therewith, an armature bar common to two or more poles of said circuit breaker, and a trip bar engageable and operable by any one of said thermally responsive means or by said common armature bar.

12. In a circuit breaker, switch members for opening a plurality of poles, latching means releasable to cause a plurality of said switch members to move from the open circuit to the closed circuit position, and releasing means for said latching means, including a plurality of conduct ing loops of bimetallic material, each energized by the current flow in one pole of said breaker, an armature bar extending across two or more poles of said circuit breaker, and a trip bar engageable and operable by any one of said conducting loops or by said armature bar.

13. In a circuit breaker, a plurality of switch members for opening a plurality of poles, a plurality of conducting loops connected in series with individual poles of said circuit breaker, a plurality of thermally responsive portions, each associated with and energized by one of said conducting loops and extending outwardly therefrom, a plurality of magnetic members, each likewise associated with and energized by one of said conducting loops, a single armature extending across two or more poles of said circuit breaker and attractable by any one of said conducting loops and its associated magnetic member, and insulatingmeans for insulating said single armature from said conducting loops at all times.

14. In electrical apparatus, a current-carrying means including a pair of leg portions, at least one of which is of bimetallic material, and means for electrically connecting said leg portions, said leg portion of bimetallic material being movable upon the occurrence of predetermined conditions to cause the actuation of said apparatus, and magnetically responsive means including means movable independently of said current-carrying means to cause the actuation of said apparatus upon the occurrence of other predetermined conditions, said leg portions and the means connecting said leg portions comprising the energizing means for said magnetically responsive means.

15. In electrical apparatus, a current-carrying means of bimetallic material including means defining a pair of leg portions and means for connecting said leg portions to form a looped conducting path, said means of bimetallic material being movable, substantially at right angles to the plane of said loop, to cause the actuation oi!v said apparatus upon the occurrence of predetermined conditions, and magnetically responsive means including means movable to cause the actuation of said apparatus upon the occurrence of other predetermined conditions, the looped conducting path formed by said leg portion and said connecting portion comprising the energizing means for said magnetically responsive means.

16. In electrical apparatus, a current-carrying means of bimetallic material including means defining a substantially U shaped portion, and

means for supporting said current-carrying means adjacent the open end of said U shaped portion, the closed end of said U shaped portion being movable to cause the actuation of said apparatus upon the occurrence of predetermined conditions, and magnetically responsive means including means movable independently of said current-carrying means to cause the actuation of said apparatus upon the occurrence of other predetermined conditions, the looped conducting path formed bysaid U shaped portion comprising, the energizing means for said magnetically responsive means.

17. In a trip device for a circuit interrupter having a plurality of poles, a plurality of thermally responsive elements, each electrically connected so as to be traversed by at least part of the current flowing in the circuit controlled by one of said poles, a movable trip bar extending across two or more poles of said circuit interrupter, said trip bar being moved during the operation of said trip device through the direct engagement therewith of one or more of said thermally responsive elements, adjustable means 01' insulating material for individually calibrating each pole of the trip device positioned between the points on said trip bar which are directly en-v gaged by said thermally responsive elements during the tripping operation, and a single means preventing adjustment of all of said calibrating means while said single means is in place.

18. In a trip device for a circuit interrupter having a plurality of poles, a plurality of bimetallic thermally responsive elements, each electrically connected so as to be traversed by at least part of the current flowing in the circuit controlled by one of said poles, and a movable trip bar extending across two or more poles of said circuit interrupter, said trip bar being moved during the operation of said trip device through the direct engagement therewith of one or more of said thermally responsive elements, said thermally responsive elements each engaging said trip bar through. individual means at least partially of insulating material, said individual means each including means permitting said thermally responsive elements to be individually calibrated and adjusted, at least when said trip device is being assembled.

19. In a trip device for a circuit interrupter having a plurality of poles, a plurality of bimetallic, thermally responsive elements, each electrically connected in the circuit controlled by one of said poles, a plurality of magnetically responsive elements each energized in response to the current flowing in the circuit controlled by one of said poles, and a movable trip bar extending across two or more poles of said interrupter, each of said bimetallic elements including a portion which is movable upon the occurrence of predetermined conditions, independently of the other thermally responsive element or elements, to directly engage and move said trip bar to effect the operation of said device, and each of said magnetically responsive elements being capable of attracting means, movable independently of said bimetallic elements, to move said trip bar to effect the operation of said device.

20. In a trip device for a circuit interrupter having a plurality of poles, a plurality of bimetallic, thermally responsive elements each electrically connected in the circuit controlled by one of said poles, a plurality of magnetically responsive elements each energized in response to the current flowing in the circuit controlled by one of said poles, and a movable trip bar extending acrosstwo or more poles of said interrupter, each of said' bimetallic elements including a portion which is movablenpon the occurrence of predetermined conditions;independently of the other thermally responsive element or elements, to directly engage and move said trip bar to effect the operation of said device, and each of said magnetically responsive elements being capable of attracting means, movable independently of said bimetallic elements. to move said bar to effect the operation of said device, said trip device including means of insulating material positioned so as to permit said trip bar to be moved to the tripped position through the actuation of one or more of said thermally responsive or said magnetically.

responsive elements, and at the same time serving to electrically insulate said elements from each other.

21. In a circuit interrupter, a main closure, means for opening and for closing the circuit disposed within said main closure, and a removable trip device for causing said interrupter to open the controlled circuit upon the occurrence of pre determined conditions, said trip device including a separate closure, and adjustable means for callbrating the tripping point of said trip device, disposed within said separate closure, said trip device and said separate closure therefor being removable as a unit from operative engagement with said circuit interrupter and said main closure, and said means for calibrating the tripping point of said trip device being adjustable only when said separate closure is opened.

22. In a circuit interrupter, a main closure, means for opening and for closing the circuit disposed within said main closure, and a removable trip device therefor, said trip device including electro-responsive means movable upon the occurrence of predetermined conditions to cause said interrupter to move to the open circuit position. means for calibrating the tripping point of said electro-responsive means, and a separate closure means for enclosing said electro-responsive means and said calibrating means, said trip device and said separate closure means being removable as a unit from engagement with said means for opening and for closing the circuit and said main closure therefor.

23. In a circuit interrupter, a closure, means for opening and for closing the circuit adapted to be disposed within said closure, and a removable trip device for causing said interrupter to open the controlled circuit upon the occurrence of predetermined conditions, said trip device including a separate closure, and a latching means for operatively engaging said means for opening and for closing the circuit, disposed Within said separate closure, said trip device and said separate closure being removable as a unit from the closure for said interrupter.

24. In a circuit interrupter, a main closure, means for opening and for closing a plurality of poles disposed within said, main closure, and a removable trip device therefor, said trip device including a plurality of electro-responsive elements, each of which is electrically connected in the circuit controlled by one of said poles, and a single closure separate from said main closure for said plurality of elements, said trip device and said closure being removable as a unit from operative engagement with said means for opening and for closing a plurality of poles and said main closure.

25. In a circuit interrupter. a main closure, means for opening and for closing a plurality of poles disposed within said main closure, and a removable trip device therefor, said irip devil-e including a base member, a plurality of elect: sponsive elements, each of which is e connected in the circuit controlled by one oi said poles, supported on said base member, a cover means likewise supported on said base, said 1 member and said cover means together form closure for said trip device, and adjustable rue-ans for individually calibrating the tripping point of each of said electro-responsive elements. at least during the assembling thereof, disposed within said closure, said trip device being removable as a unit from said interrupter without necessitating the removal of said cover.

26. In a circuit interrupter, a main closure, means for opening and for closing a plurality of poles disposed within said main closure, and a removable trip device therefor, said trip device including a plurality of electro-responsivr ele ments, each of which is electrically connected in the circuit controlled by one of said poles, adjustable means for individually calibrating the tripping point of each of said electro-responsivc elep and said calibrating means, said trip device and said closure being removable as a unit from operative engagement with said means for opening and for closing a plurality of poles and said main closure.

27. In a multi-pole circuit interrupter, a main base member, contact means for defining a plurality of poles supported thereon, actuating means for said contact means, and a removable trip device which is operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open-circuit position, said trip device including a base, a plurality of current-carrying, electroresponsive elements, each of which is connected in the circuit controlled by one of said poles, a single trip bar extending laterally across all 01 said poles and being movable by any one of said electro-responsive elements to cause the operation of said trip device, and a closure which coacts with said base so as to substantially completely enclose said trip bar and the actuating elements therefor, said trip device and said closure being normally supported upon said main base member and being removable as a unit from operative engagement with said interrupter.

28. In a multi-pole circuit interrupter, a main base member, contact means for defining a plurality of poles supported thereon. actuating means for said contact means, and a removable trip device which is operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the opencircuit position, said trip device including a base, a plurality of current-carrying bimetallic, thermally responsive elements supported thereon, each of said elements being electrically connected in the circuit controlled by'one of said'poles, a single trip bar, which is likewise supported on said base and which extends laterally across all of said poles-said trip bar being moved, during the normal operation of said trip device, through the direct engagement therewith of one or more of said thermally responsive elements, said thermally responsive elements each engaging said trip bar through means which permits said elements to be individually calibrated, and a closure adapted to cooperate with said trip base to substantially completely enclose said trip bar and said electro-responsive elements, said trip device and said closure being normally supported upon said base member and being removable as a unit from operative engagement with said interrupter.

29. In a mult-i-pole circuit interrupter, a main base member, contact means for defining a plurality of poles supported thereon, actuating means for said contact means including a member mov able to cause said contact means to be moved to the open circuit position, and a removable trip device, which includes a base, latching means supported thereon for normally restraining said movable member, releasing means for said latching means, and a closure which cooperates with said base so as to substantially completely enclose said releasing means, said releasing means being ontirely supported on said base and including a plurality of conducting loops of bimetallic material, each energized by the current flow in one pole of said breaker, a plurality of magnetizing members, each likewise energized by the current flow in one pole of said breaker, an armature bar extending across two or more poles of said interrupter and being movable by the attraction of any one of said magnetizing members, and a trip bar also extending across two or more poles of said interrupter, said trip bar being movable by any one of said bimetallic conducting loops or by said armature bar to cause the release of said latch means, said trip device and said closure being normally supported upon said main base member and being removable as a unit from operative engagement with said interrupter.

30. In a trip mechanism for a circuit breaker,

means movable to cause opening of said circuit the occurrence of a predetermined overload, and magnetic means associated with and energizedby current flow in said looped conducting portion of bimetallic material to cause the movement of said movable means upon occurrence of a short circuit of greater value than said predetermined overload,

31. In a trip device for a circuit breaker, a U shaped conducting loop formed entirely of bimetallic material movable laterally when heated by the flow of current therein to trip said circuit breaker upon the occurrence of a predetermined electrical condition, a U shaped member of magnetic material interlinked with said U shaped conducting loop of bimetallic material, and an armature in cooperative relation to said U shaped magnetic member to trip said circuit breaker upon the occurrence of another predetermined (318C! trical condition.

32. In a trip device for a circuit breaker, a looped conducting means having both sides of the loop of bimetallic material electrically connected in circuit with said circuit breaker and having a portion heated by the flow of current therehrough, thermally responsive means also of bimetallic material extending beyond the bend of said loop and being in thermally conductive relation to said heated portion of the conducting means to permit flow of heat by conduction from saidheatcd portion to other parts of saidther-i molly responsive means of bimetallic material to bend it laterally to trip the circuit breaker, and means including a member of magnetic material having a portion disposed within said loop and being energized by the flux set up by the current flow through said loop to also trip the circuit breaker.

33. In a trip device for a circuit breaker a U shaped current-conducting loop formed entirely of bimetallic material and having a portion of bimetallic material extending outwardly therefrom, both sides of said U shaped loop being fixedly mounted adjacent the open end of the U and said U shaped loop being laterally movable adjacent its closed end and a magnetically responsive element including a member of mag netic material disposed about and having a portion extending between the legs of said U for tripping the breaker in response to predetermined current conditions in the circuit with which it is associated.

3-1. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit through a plurality of poles, actuating means for said Contact means, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a plurality of thermally responsive elements, means for connecting each of said elements in current responsive relationship with the circuit controlled by one of said poles, a plurality of core members, means for energizing each of said core members in response to the current flowing in the circuit controlled by one of said poles, a single armature extending across two or more poles of said interrupter which armature is movable from a normal inoperative position to an operative position by the attraction of any one of said core members, and a trip bar extending across two or more poles of said interrupter, said trip bar being movable to effect the actuation of said trip device in response to the operation of any one of said thermally responsive elements or by said single armature.

Cal

35. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit through a plurality of poles, actuating means for said contact means, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means from the closed circuit to the open circuit position, said trip device including a base, a plurality of bimetallic, thermally responsive elements, each supported on said base adjacent one end thereof, the other end of each of said bimetallic elements being movable on the occurrence of predetermined conditions, means for connecting each of said bimetallic, thermally responsive elements into current responsive relationship with one of the poles of said interrupter, a plurality of U shaped core members affixed to said base member and energized in response to the current flowing through one of the poles of said interrupter, a common armature comprising a flat plate of magnetic material extending across a plurality of the poles of said interrupter, the plane of said plate being normally disposed substantially normal to said base, means for pivotally supporting said common armature in such manner that it is attractable to any one of said core members, and a pivotally supported trip bar extending across a plurality of the poles of said interrupter, said trip bar being movable from a normal untripped position to a tripped position to effect the actuation of said trip device by movement of any one of said thermally responsive elements or by said common armature.

36. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit through a plurality of poles, actuating means for said contact means including a member movable to cause said actuating means to move said contact means from the closed circuit to the open circuit position, and a trip device which is operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a pivotally supported member movable from a normal inoperative position to an operative position in order to effect the operation of said trip device, a plurality of bimetallic, thermally responsive elements each energized in response to the current flowing in one of the poles of said interrupter, a plurality of core members each energized in response to the current flowing in one of the poles of said interrupter, a single armature bar which extends across a plurality of the poles of said interrupter and which includes means attractable by any one of said core members upon the occurrence of predetermined conditions to move said armature bar from a normal inoperative to an operative position, and a trip bar which also extends across a plurality of the poles of said interrupter and which is movable from a normal untripped to a tripped position by any one of said thermally responsive elements or by said armature bar, said trip bar normally engaging a portion of said movable member with a latching engagement and preventing that member frommoving' to effect the operation of. said trip device until said trip bar has been moved to the tripped position, in which position said trip bar disengages said movable member.

37. In a trip device for a multi-pole circuit interrupter. a member movable from a normal inoperative position to an operative position to effect the operation of said trip device, a plurality of thermally responsive elements, means for energizing each of said thermally responsive elements in response to the current flowing in the circuit controlled by one of the poles of said interrupter, a plurality of core members of magnetic material, means for energizing each of said core members in response to the current flowing in one of the poles of said interrupter, a common armature bar extending across a plurality of poles of said trip device, said armature being movable from a normal inoperative position to an Operative position by the attraction of any one of said core members, means biasing said common armature bar to the inoperative position, means of non-magnetic material positioned intermediate said armature bar and said core members in order that said armature bar may not be moved into direct contact therewith, a single trip bar extending across a plurality of the poles of said trip device, said trip bar being movable from a normal untripped position to a tripped 5 position by any one of said thermally responsive elements or by said common armature, a portion of said member movable to effect the operation of said trip device engaging said trip bar with a latching engagement and said trip bar being moved to effect the release of this latching engagement during the tripping operation.

38. In a trip device for a multi-pole circuit interrupter, a pivotally supported member movable from a normal inoperative position to an operative position to effect the operation of said trip device, means biasing said movable member to the operative position, a plurality of bimetallic, thermally responsive elements, means for energizing each of said bimetallic elements in response to the current flowing in the circuit controlled by one of the poles of said interrupter, a plurality of core members of magnetic material, means for energizing each of said core members in response to the current flowing through one of the poles of said interrupter, a single armature bar comprising a flat strip of magnetic material extending across a plurality of the poles of said device and being attractable from 9. normal inoperative position to an operative position by any one of said core members, means biasing said armature bar to said inoperative position, means of non-magnetic material positioned intermediate said armature bar and each of said core members for preventing said bar from sticking during the operation of said trip device, a pivotally supported trip bar extending across a plurality of the poles of said device, a portion of said member movable to effect the operation of said trip device engaging said trip bar with a latching engagement, and said trip bar being movable by any one of said bimetallic elements or by said common armature to effect the release of this latching engagement and thereby allow said movable member to move under the action of its biasing means to effect the operation of said trip device, and means biasing said trip bar into latching engagement with said mov able member.

39. In a trip device for a circuit interrupter having a plurality of poles, a plurality of current-carrying bimetallic elements each energized in response to the current flow one of the poles of said interrupter, a plurality of core members of magnetic material, means for energizing each of said core members in response to the current flowing in one of the poles of said device, a pivotally supported common armature for said plurality of core members, said armature extending across a plurality of the poles of said interrupter and being movable from a normal in operative position to an operative position by the attraction of any one of said core members. means biasing said armature bar away from said core members, a pivotally supported trip bar extending across a plurality of the poles of said device, said trip bar being rotatable from a normal untripped position to a tripped position where it effects the operation of said device by any one of said thermally responsive elements or by said common armature, and means biasing said trip bar to said untripped position.

40. In a circuit interrupter separable contact means for opening and for closing the electrical circuit through a plurality of poles, actuating means for said contact means, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a plurality of bimetallic, thermally-responsive elements each of which is energized in response tothe current flowing in one of the poles of said interrupter, a plurality of core members each or which is likewise energized in response to the current flowing in one o! the poles of said interrupter, a pivotally supported armature'bar extending laterally across a plurality of the poles of said device, said armature bar including means attractable by any one of said core members and being movable from a normal inoperative position to an operative positionby the attraction of any one of said core members, a common trip bar which extends across a plurality of the poles of said interrupter, said trip bar being movable from a normal untripped position to a tripped position to effect the operation of said trip device by any one of said bimetallic elements or by said armature bar, said bimetallic elements being positioned in the space intermediate said armature bar and said actuating means for said interrupter.

41. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit through a plurality of poles, actuating means for said contact means, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a plurality of bimetallic, thermally responsive elements, a plurality of core members each energized in response to the current flowing in one of the poles of said interrupter, a pivotally supported armature bar extending laterally across a plurality of the poles of said device, said armature bar including means attractable by any one of said core members and being movable from a normal inoperative position to an operative position by the attraction of any one of said core members, and a pivotally supported trip bar extending across a plurality of the poles of said trip device, said trip bar being movable from a normal untripped position to a tripped position to effect the operation of said trip device by any one of said bimetallic elements or by said armature bar, said bimetallic elements being positioned in the space intermediate said trip bar and said actuating means for said circuit interrupter.

42. In a circuit interrupter, separable contact means for opening and for closing a plurality of poles, actuating means for said contact means including a member movable upon the occurrence of predetermined conditions to cause said contact means to move from the closed circuit to the open circuit position, and a trip device for cooperating with said actuating means, said tripdevice including a pivotally supported latch' which normally restrains said movable member from moving to cause said contact means to move to the open circuit position, a plurality or bimetallic thermally responsive elements positioned adjacent one another, a plurality of core members each energized in response to'thc current flowing in one of the poles of said interrupter, a pivotally supported armature bar extending laterally across a plurality of the poles of saiddevicesaid armature bar including means attractablc by any v from a normal untripped position to a tripped position to effect the release of said latch inresponse to the movement of any one of said bimetallic elements or by said armature bar, the

axis of rotation of said trip bar and saidlatchv being substantially parallel to each other andsaid bimetallic elements being positioned, gencr ally, in the'space between said parallel axes.

43. In a multi-pole circuit interrupter, a contact member movable to open and close the cir- 'cuit through each of a plurality of the poles of the circuit interrupter, means for moving. a plurality of said contact members to open circuit position, a movable member in response to movement of which the aforesaid means moves. a pinrality of said contact members to open circuit position, and tripping means for initiating said movement of the movable member, said tripping means including a plurality of conducting means each connected to be traversed by at least part of the current flowing through one poleof the cirr cuit interrupter, a plurality of pole pieces of 'mag-, netic material each magnetically 1energized'by. one of said conducting means, and an armature bar extending across said plurality of pole pieces, said armature bar including a plurality of portions of magnetic material each attractable to one of said pole pieces and each of said portions of magnetic material being moved toward-its pole.

piece upon the attraction of any one of said'portions of magnetic material by its pole piece.

44. In a multi-pole circuit interrupter, a contact member movable to open and close the circuit through each of a plurality of the poles of the circuit interrupter, means for moving a plurality of said contact members to open. circuit position, a movable me'inber in response to movement of which the aforesaid means moves a plurality of said contact members to open circuit position, and tripping means for initiating said movement of the movable member, said tripping means including a plurality of conducting means each connected to be traversed by at least part of the current flowing through one pole of the circuit interrupter, a plurality of pole pieces of magnetic material each magnetically energized by one of said conducting means, and an armature bar extending across said plurality of pole pieces, said armature bar comprising a single member of magnetic material attractable by any one of said pole pieces.

45. In a multi-pole circuit interrupter, a contact member movable to open and close the circuit through each of a plurality of the poles of the circuit interrupter, means for moving a plurality of said contact members to open circuit position, a movable member in response to movement of which the aforesaid means moves a plueach connected to be traversed by at least part of the current flowing through one pole of the circuit interrupter, a plurality of pole pieces of magnetic material each magnetically energized by one of said conducting means, and an armature bar having its longitudinal axis extending across all of said pole pieces, said armature bar being pivoted about an axis generally parallel to its longitudinal axis and including a plurality of portions of magnetic material each attractable to one of said pole pieces to rotate said armature bar and all of said portions of magnetic material about said pivotal axis extending longitudinally thereof toward said pole pieces.

46. In a multi-pole circuit interrupter, a contact member movable to open and close the circuit -through each of a plurality of the poles oi the circuit interrupter, means for moving a plurality of said contact members to open circuit position, a movable member in response to movement of which the aforesaid means moves a plurality of said contact members to open circuit position, and tripping means for initiating said movement of the movable member, said tripping means including a plurality of conducting means each connected to be traversed by at least part of the current flowing through one pole of the circuit interrupter, a plurality of pole pieces of magnetic material each magnetically energized by one of said conducting means, and an armature bar 7 having its longitudinal axis extending across all of said pole pieces, said armature bar being pivoted about an axis generally parallel to its longitudinal axis and comprising a single member of magnetic material attractable by any one of said pole pieces to cause rotation of said armature bar about its pivotal axis and bring said single member of magnetic material closer to each of said plurality of pole pieces.

47.In a multi-pole circuit breaker, a plurality of contact members movable to open and close the circuit through a plurality of the poles or the circuit breaker, means for moving a plurality of said contact members to open circuit position, a movable member in response to movement of which the aforesaid means moves said plurality of contact members to open circuit position, a main base on which said contact members, said means for moving the contact members and said movable member are mounted, and a removable trip unit including a separate base removably secured to said main base and having mounted thereon a plurality of conducting means each responsive to the current through one pole of the circuit breaker, a plurality of pole pieces 01' magnetic material each energized magnetically by one of said conducting means, and an armature bar in response to movement of which said movable member on the main base causes said plurality of contact members to move to open circuit position, said armature bar extending across said plurality of pole pieces and including a plurality of portions of magnetic material each aitractablc by one of said pole pieces, and all oi said portions of magnetic material being movable together as a rigid unit upon the attraction of any one of said portions.

48. In a multi-pole circuit breaker, a plurality of contact members movable to open and close the circuit through a plurality of the poles of the circuit breaker, means for moving a plurality of said contact members to open circuit position, a movable member in response to movement of which the aforesaid means moves said plurality 01' contact members to open circuit position, a main base on which said contact members, said means for moving the contact members and said movable member are mounted, and a removable trip unit including a separate base removably secured to said main base and having mounted thereon a plurality of conducting means each responsive to the current through one pole of the circuit breaker, a plurality of pole pieces of magnetic material each energized magnetically by one of said conducting means, and an armature bar in response to movement of which said movable member on the main base causessaid plurality of contact members to move to open circuit position, said armature bar extending across said plurality of pole pieces and comprising a single member of magnetic material attractable by any one oi said pole pieces.

49. In a circuit interrupter, a main base. separable contact means tor opening and for closing the electrical circuit through a plurality of poles supported thereon, actuating means for said contact means. a removable trip device which is operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a base, a plurality of bimetallic, thermally-responsive elements each individually connected so as to be traversed by at least part of the current flowing in the circuit controlled by one of said poles, a trip bar extending laterally across two or more poles of said interrupter, said trip bar being movable from a normal inoperative position to an operative position to eflect the operation of said trip device through the direct engagement therewith of one or more of said thermally responsive elements, and closure means which coact with said main and said trip base to enclose the several structural elements of said interrupter, said trip device, including said trip base, being normally supported upon said main base and being removable as a unit from operative engagement with said interrupter.

50. In a circuit interrupter, a main base, separable contact means for opening and for closing the electrical circuit through a plurality oi poles supported thereon, actuating means for said contact means, a removable trip device onerable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a base, a plurality oi bimetallic. thermally-responsive elements each electrically connected so as to be traversed by at least part oi the current flowing in the circuit controlled by one of said poles, a trip bar pivotally supported on said trip base so as to extend across two or more of the poles of said interrupter, said trip bar being movable from a normal inoperative to an operative position to eilect the operation of said trip device through the direct engagement therewith of one or more of said thermally-responsive elements,

and means of insulating material positioned between the points on said trip bar which are directly engaged by said thermally-responsive elements during the tripping operation, and closure means which coacts with said main base and .said trip base to substantially, completely enclose the several structural elements of said inr tcrrupter, said trip device, including said trip the electrical circuit through a plurality of poles supported thereon, actuating means for said contact means, a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a plurality of bimetallic, thermally-rcspons.ive elements, each electrically connected so as to be traversed by at least part of extending-across two or more of the poles of said interrupter, said trip bar being movable from a normal inoperative to an operative position to effect the operation of said trip device through the direct engagement therewith of one or more of said thermally-responsive elements, said thermally-responsive elements each I engaging said trip bar through individual means which include means for permitting said thermally-responsive elements to be individually calibrated and adjusted at least when said trip device is being assembled, and closure means which coacts with said main base and said trip base to enclose the several structural elements of said interrupter, said trip device, including said trip base, being normally supported upon said main base and being removable as a unit from operable engagement with said interrupter.

52. In a circuit interrupter, a main base, separable contact means for opening and for closing the electrical circuit through a plurality of poles supported thereon, actuating means for said contact means, and a trip device operable on the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device including a base, a plurality of bimetallic, thermally-responsive elements supported on said base, each of said elements being energized in response to the current flowing in the circuit controlled by one of said poles, a plurality of core members, each of said core members being likewise energize-:1 in response to the current flowing in the circuit controlled by one of said poles, an armature bar extending across two or more poles of said interrupter, which armature bar is movable from a normal inoperative position to an operartivc position by the attraction of any one of said means for permitting said thermally responsive element to be individually calibrated and adjusted a least when said trip device is being assembled. said trip device, including said trip base, being normally Si :ported upon main base and being reino- We as a unit from operative engogement with said interrupter.

53. In circuit interruper, a main bas sop-- arobi'; ",ontact means for epening and for closing the electrical circuit through a plurality of poles supported thereon, actuating means for said contact means, a trip device operable on the occurrence of predetermined conditions to cause said actuating means to move said contact means to the open circuit position, said trip device ineluding a base, a plurality of bimetall'c, thermally-responsive elements supported on said base, each of said elements being energized in response tot-he current flowing in the circuit controlled by one of said poles, a plurality of core members, each of said core members being, likewise energzcd in response to the current flowing in the circuit controlled by one of said poles, an armature bar pivotally supported on sa d trip base and extendingacross two or more poles of said intcrrupter, which armature baris movable from a normal inoperative position to an operative position by the attraction of any one of sa d core members, a trip bar also pivotally supported on said trip base, said trip bar being movable from a normal inoperative to an operative position to effect operation of said trip device in response -t6' the operation of any one of said thermallyrcsponsivc elements or in response to movement of said armature bar, said thermally responsive elements each engaging said trip bar through individual means which include means for permitting said thermally responsive element to be individually calibrated and adjusted at least when said trip device is being assembled, and closure means which eoacts with said main base and said trip base to enclose the several structural elements of said interrupter, said trip device, including said trip base, being normally supported upon said main base and being removable as a unit in operable engagement with said interrupter.

54. In a circuit interrupter, a base having mounted thereon separable contacts for opening and for closing a plurality of poles, actuating means for said contacts, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means from the closed circuit to the open circuit position, said trip device including a plurality of bimetallic thermally responsive elements each supported at one end on said base and movable at the other end, a common trip bar which extends across a plurality of the poles of said interrupter, and said trip bar being movable I by movement of the movable end of any one of 'ments extending upwardly from the base in the space intermediate said trip bar and said actuating means for the contacts.

55. In a circuit interrupter, a base having mounted thereon separable contacts for opening and closing the circuit, an actuating mechanism for said contacts, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move one of said contacts from the closed circuit to the open circuit position, said trip device including a trip member upstanding from the base and pivotally mounted to be movable at its upper end, a bimetallic member mounted at one end to extend upwardly from the base, said bimetallic member being movable at its upper end to move the upper end of said trip member, and said bimetallic member being positioned between said trip mem ber and said actuating mechanism.

56. In a multi-pole circuit interrupter, a base having mounted thereon a plurality of contacts movable to open and close the circuit through a plurality of the poles of the circuit interrupter, an actuating mechanism for moving all of said contacts, and a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to open said plurality oi contacts, said trip device including a trip member extending outwardly from the base and being pivotally mounted adjacent its end nearest the base, said trip member being movable at its upper end and having a portion adjacent its upper end extending across a plurality of the poles of the circuit interrupter, a plurality of bimetallic elements each responsive to the current flowthrough one pole of the circuit interrupter, said bimetallic elements being each mounted at one end on the base and extending outwardly therefrom on the side of said trip member adjacent said operating mechanism, and the upper end of each of said bimetallic elements being movable to move the upper end of said trip member having the portion extending across the plurality o! poles.

5'!. In a circuit interrupter, a main closure including a base and a cover, means for opening and iorclosing thecircuit disposed within said main closure, and a removable trip device for causing said interrupter to open the controlled circuit upon the occurrence of predetermined conditions, said trip device including a separate base mounted on the main base and a separate covering member, and adjustable means for calibrating the tripping point of said trip device, disposed under said separate covering member, said trip device and said separate base-and covering member being removable as aunit from operative engagement with said circuit interrupter and said main closure with said separate covering member in place on the trip device, and said means for calibrating the tripping point of said trip device being adjustable only when said separate covering member is opened.

HARLAN S. GANO. KILLER D; DORM. 

